<Superscript>57</Superscript>Fe emission Mössbauer spectroscopy following dilute implantation of <Superscript>57</Superscript>Mn into In <Subscript>2</Subscript>O<Subscript>3</Subscript>

Emission Mössbauer spectroscopy has been utilised to characterize dilute ⁵⁷Fe impurities in In ₂O₃ following implantation of ⁵⁷Mn (T _1/2 = 1.5 min.) at the ISOLDE facility at CERN. From stoichiometry considerations, one would expect Fe to adopt the valence state 3 + , substituting In ³⁺, however the spectra are dominated by spectral lines due to paramagnetic Fe²⁺. Using first principle calculations in the framework of density functional theory (DFT), the density of states of dilute Fe and the hyperfine parameters have been determined. The hybridization between the 3d-band of Fe and the 2p band of oxygen induces a spin-polarized hole on the O site close to the Fe site, which is found to be the cause of the Fe²⁺ state in In ₂O₃. Comparison of experimental data to calculated hyperfine parameters suggests that Fe predominantly enters the 8b site rather than the 24d site of the cation site in the Bixbyite structure of In ₂O₃. A gradual transition from an amorphous to a crystalline state is observed with increasing implantation/annealing temperature.     

Latest results from Double Chooz

Double Chooz is a short-baseline neutrino disappearance experiment. It detects ν? _e produced in the power plant of Chooz, France, where is located. The main goal of the experiment is the measurement of θ₁₃ mixing angle and in 2011 for the first time the experiment observed an indication for a non zero value of such an oscillation parameter. The mixing angle was successively measured using only the far detector finding the best fit value of sin²(2θ₁₃) = 0.090 _?0.029 ^+0.032 . The near detector is under construction and will start data taking by the middle of 2014 allowing the reduction of the systematic errors. In this paper I make a review of the Double Chooz experiment, focusing in particular on the latest results of the measurement of the mixing angle θ₁₃ relying on the neutron absorption on Gadolinium. I also present results proving the capability of Double Chooz to identify the ortho-positronium. This has been done in an event-by-event basis for the first time in a large liquid scintillator experiments, and can be an additional handle for the electron/positron discrimination in future detectors based on such technology.     

The spatial string tension and dimensional reduction in QCD

The spatial string tension is calculated in 2+1 flavor QCD with a physical strange quark mass and almost physical light quark masses on lattices with N_t=4,6 and 8. The results are compared with predictions of dimensionally reduced QCD. They suggest that dimensional reduction works also in the presence of light dynamical quarks down to temperatures of about 1.5T_c.     

Spectres de vibration en série cyclobutanique II. Acides cyclobutanecarboxyliques C4H7-COOH ET C4H7-COOD

The infrared and Raman spectra of C₄H₇-COOH and C₄H₇-COOD were studied and assignments were made for the observed frequencies. In the liquid state, the acids exist chiefly as centrosymmetrical closed dimers with a puckered configuration of the cyclobutane rings. Analysis of the polarization ratio of the Raman lines led to the conclusion that these dimers have C_i symmetry.